The present invention relates to a wiper arm for supporting a wiper blade for oscillatory rotary movement with respect to a windscreen and the method of making a wiper arm.
A wiper arm is connectible to a wiper blade and supports the wiper blade with respect to a windscreen to be wiped with a force or load acting to maintain the wiper blade in contact with the windscreen during the oscillatory rotary movement of the wiper blade across the windscreen even at high vehicle speeds. The wiper arm is securely attached at one end to a drive shaft for imparting oscillatory rotary movement to the wiper blade connected at an opposite end of the wiper arm. A wiper arm is typically movable from the primary position where the wiper blade is engaged against the windshield, to a secondary position where the wiper blade is spaced from the windscreen allowing routing maintenance and/or cleaning of the wiper blade assembly. These movement requirements of the wiper arm have led to conventional wiper arms being complex assemblies with many individual parts, which are costly to manufacture. Typically, two spring mechanisms have been required to provide the ability to move between the primary and secondary positions of the wiper arm. In some instances, the first spring mechanism is provided by the resiliency of the material of the wiper arm itself, while the other spring mechanism is provided by a separate coil spring. When using a separate coil spring, the wiper arm structure must be modified to at least partially enclose the coil spring to protect it from the elements. The head of the wiper arm typically engages a conventional splined cylindrical drive shaft using a rigid, matching splined socket adjacent one end of the wiper arm.
It would be desirable in the present invention to provide a wiper arm having a simpler structural configuration while maintaining the ability to move from a primary position to a secondary position allowing firm engagement with a windscreen during wiping movement with the wiper arm in the primary position and permitting routine maintenance and cleaning of the wiper blade when the wiper arm is in the secondary position spaced from the windscreen. It would be desirable in the present invention to provide a wiper arm of a simple construction capable of cost effective production. It would be desirable in the present invention to provide a method of manufacturing a wiper arm of simple construction in a cost effective manner.
According to the present invention, a method for manufacturing a wiper arm is disclosed. The wiper arm supports a wiper blade for oscillatory rotary movement with respect to a windscreen. The method includes the steps of forming a body having a first end and a second end, where the first end of the body is connectible to and supportable by a drive shaft for imparting oscillatory rotary movement, and where the second end of the body is connectible to and supporting a wiper blade. The method of manufacturing according to the present invention forms a torsional region of the body capable of toggle action defined by two stable positions lying spaced at opposite sides of an unstable range of movement, where one of the two stable positions exerts downward pressure on a wiper blade connectible to the body for engagement against a windscreen to be wiped. In the preferred configuration, the method initially forms the torsional region of the body to be defined by first and second torsional members, where each torsional member when in a relaxed state has a free end cantilevered outwardly from the first end of the body and spaced from one another. The method for manufacturing according to the present invention in the preferred configuration subsequently flexes each torsional member from the relaxed state into a flexed state such that the free ends engage one another and thereafter the free ends of the torsional members are connected with respect to one another when in the flexed state.
A wiper arm according to the present invention, such as a wiper arm manufactured by the method according to the present invention, supports a wiper blade for oscillatory rotary movement with respect to a windscreen. The wiper arm includes a body having a first end and a second end, where the first end of the body is connectible to and supportable by a drive shaft for imparting oscillatory rotary movement, and where the second end of the body is connectible to and supports a wiper blade. The wiper arm according to the present invention includes a torsional region of the body capable of toggle action and located between the first and second ends of the body. The toggle action is defined by two stable positions lying spaced at opposite sides of an unstable range of movement, where one of the two stable positions exerts downward pressure on a wiper blade connectible to the body for engagement against a windscreen to be wiped.
In the preferred configuration of the wiper arm, the torsional region is defined by first and second torsional members initially formed in a relaxed state, where each torsional member has a free end cantilevered outwardly from the first end of the body and spaced from one another, where each torsional member is subsequently flexed into a flexed state such that the free ends engage one another. According to the preferred embodiment of the wiper arm means are provided for connecting the free ends of the torsional members with respect to one another when in the flexed state.
Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings.